Many electrical devices are used in applications where it may be desirable to restrict access to their use, for example, where such use may be dangerous when involving unqualified individuals or where an electrical device is not functioning properly. While access to some electrical devices may be restricted by electronic safeguards, such as, for example, by electronic passcode, a simpler arrangement for preventing use of an electrical device involves use of a electrical plug lockout device, in which an enclosure or other obstruction is lockably secured to one or more prongs of an electrical plug by which the electrical device is powered, thereby preventing electrical connection of the plug to a power source, such as a wall socket.